Scbew-pbopeller



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UNITED sTATEs PATENT oFFicE.

GEORGE E. SAFFORD, OF NEW YORK, N. Y.

SCREW-PROPEILLER.

Specification of Letters Patent No. 28,117, dated March 1, 1859'.

To all 'whom t may concern:

Be it known that I, GEORGE E. SAFFORD, of New York, in the county of New York and State of New York, have invented an Improvement in Propellers, the construction and operation of which I have described in the following specification and illustrated in its accompanying drawings with suflicient clearness to enable competent and skilful workmen in the arts to which it pertains or is most nearly allied to make and use my invention.

My said invention consists in hanging the blades to the shaft by means of a double hub, or hub made in two parts as herein after described with diagonal notches in the boss in which notches the blades are secu/red as more fully set forth below.

Figure l is a side elevation of my improved propeller. F ig. 2 is an end elevation.

A is the shaft, which is made and hung as usual. The mode of constructing, hanging, and operating it is well known to all ship and engine builders, and require no description in this connection or representation in the drawings.

B are the parts which constitute the hub of the wheel. `These are nearly disks, but have lugs or projections b upon them, between which are notches or slots for the reception of the blades C. These notches should properly be made dovetailing so as to hold the blades should one of the pinsfl work loose or break. These pins pass through the lugs b and through the blades C to secure the latter in place. The blades are made nearly or quite flat, of the proper size and form to answer the purpose for which they are intended. Their' form, as I have thought best to construct them, is fully and clearly shown in the drawings.

The parts B are attached to the shaft in y such positions as to give the right lead to the bucket, and at the same time make the notches correspond in direction and position.

By this construction I secure the blades very lirmly in position, and support them in a much more substantial manner than is done by the old mode of casting the wheel whole or securing the blades by bolting them upon projecting arms; and for propellers of light dip the blades operate more freelyT than in the old construction.

The blades can be easily taken out and new ones put in, should it be necessary, by driving out the pins cl, and driving the blades out endwise.

By this constructionlightness and strength are very happily combined and the facility with which the blades may be removed and replaced make the wheel an easy one to keep 1n repair.

It is obvious that a larger number of blades may be used should it be desired, but I consider three the most economical number for a stern propeller. In a side propeller it may be desirable to use four or five or even more.

The particular improvement which constitutes my said invention and which I claim as having been originally and first invented by me is- The hub B B made in two disks with spiral or inclined slots to receive the floats, when the ioats are removably secured to rthe hub in the manner described/andV the whole being constructed substantially as and for the purpose set forth.

G. E. SAFFORD. Witnesses:

H. W. BOARDMAN, Trios. B. I-Iow. 

